Traumatic brain injury (TBI) appears to be associated with an increased risk of dementia in adults 55 and older, researchers reported online ahead of print October 27 in JAMA Neurology.
Controversy exists about whether there is a link between a single TBI and the risk of developing dementia. According to the CDC, Americans 55 and older account for more than 60% of all hospitalizations for TBI, with the highest rates of TBI-related emergency department visits, inpatient stays, and deaths happening among patients age 75 and older. Therefore, understanding the effects of a TBI and the development of dementia among middle-aged or older adults has important public health implications.
Raquel C. Gardner, MD, Clinical Instructor and Behavioral Neurology Fellow at the University of California, San Francisco, and colleagues examined the risk of dementia among adults age 55 and older with recent TBI, compared with adults with non-TBI body trauma (NTT), which was defined as fractures but not of the head or neck. The study included 164,661 patients identified in a statewide California administrative health database.
A total of 51,799 patients with trauma (31.5%) had TBI. Of those, 4,361 patients (8.4%) developed dementia, compared with 6,610 patients (5.9%) with NTT. The average time from trauma to dementia diagnosis was 3.2 years, and it was shorter in the TBI group, compared with the NTT group (3.1 vs 3.3 years). Moderate to severe TBI was associated with increased risk of dementia in persons age 55 or older, and mild TBI at age 65 or older increased the dementia risk.
“Whether a person with TBI recovers cognitively or develops dementia, however, is likely dependent on multiple additional risk and protective factors, ranging from genetics and medical comorbidities to environmental exposures and specific characteristics of the TBI itself,” the authors noted.
In a related editorial, Steven T. DeKosky, MD, Professor and Chair, Department of Neurology, University of Pittsburgh School of Medicine, stated that “Judicious use of data by skilled researchers who are familiar with the entire range of dementia research from pathobiology to health care needs will enable us to ask important questions, evolve new or more informed queries, and both lead and complement the translational questions that are before us. Dementia is both a global problem and a pathological conundrum; thus, the complementary use of big data and basic neuroscience analyses offers the most promise.”